Vented closure



3,071,276 VENTED CLGFsURE Fred G. Pellett, Maumee, and Richard K.Fiaskamp,

Toledo, Ohio, assignors to Owens-illinois Glass Zornpany, a corporationof Ohio Filed Aug. 23, 196i Ser. No. 51,396 (Ilaims. (Cl. 215-56) Thepresent invention relates to a closure for a container such as a bottle,jar, can or the like and more particularly to a so-called ventingclosure capable of releasing gaseous pressure occurring in saidcontainer.

it is known that certain products such as bleaching or hypochloritesolution when sealed in a container decompose giving ofi a gaseousby-product which tends to create a pressure within the container. Thispressure can prove very dangerous in that it can reach explosiveproportions, particularly if the container should be stored in a warmplace, such that a glass container can be shattered with seriousresults. In certain instances the pressure may not reach suchproportions as to rupture the container but will give rise to apotentially dangerous situation wherein a slight blow against thebottle, as in normal handling, will cause the bottle to explode andcause serious accidents. Attempts have been made to provide a containerwith a cap which would continuously relieve the pressure in thecontainer. However, such attempts have resulted in caps which have hadone or more serious limitations such as reduced sealing efiiciencywhereby leakage of the liquid occurs or excessive cost. Accordingly itwould be most beneficial and desirable to the bottle cap art to providea new type of cap which would be free of the aforementioned shortcomingsof presently used vented closures.

It is, therefore, an object of this invention to provide a ventedclosure for containers which tend to accumulate gaseous pressures.

A further object of this invention is to provide a vented closure whichwill permit the escape of gas from a container but inhibit the entranceof moisture.

A further object of this invention is to provide a vented closure whichwill permit the escape of gas from a container but prevent the exit ofthe liquid contents of the said container.

A further object of this invention is to provide a vented closure whichwill prevent the build up of dangerous gaseous pressures in a containerwhose contents is normally a liquid or solid but subject to liberating(spontaneously or under mild conditions of temperature) gaseousby-products such as oxygen, carbon dioxide, sulfur dioxide, and thelike.

These and other objects are attained by the construction shown in theaccompanying drawing wherein for purposes of illustration an embodimentof the invention is shown and wherein:

FIG. 1 is a vertical section of a neck of a bottle and a venting closuremade in accordance with this invention;

FIG. 1A is a fragmentary vertical section of the porous plastic layershown in FIG. 1;

FIG. 2 is a view similar to FIG. 1 but of a preferred modifiedconstruction;

FIG. 2A is a vertical fragmentary section of the layers underlying thecap of FIG. 2;

Fatented Jan. 1, 1963 FIG. 3 is a view similar to FIG. 2 but of afurther modification; and

FIG. 3A is a vertical fragmentary section of the several layersunderlying the cap of FIG. 3.

Referring now more particularly to the drawing, there is shown the upperpart of a container 1 having a neck '7 with screw threads 8 and adaptedto engage the screw lugs 9 of venting closure 2 having a cap or cover 4and a depending skirt 3. Positioned within the skirt and under the capof the closure is a liner 5 of microporous piastic. By employing the capof FIG. 1 it has been found that the gaseous products generated in thecontainer will permeate the plastic liner 5 and escape to space it andthence to the air along the threaded portions where the cap engages theneck of the bottle thereby preventing the build up of dangerouspressures within the container.

FIG. 2 represents a modification in which a porous backing liner lift orporous disc of paper board has been used with the layer or liner 5 ofmicroporous plastic or facing.

FIG. 3 represents a further modification in which an adhesive layer 12has been placed between the paper board and microporous plastic layer.In both FIG. 2 and FIG. 3 the gases liberated in container 1 permeatethe various layers and escape to the air by way of openings existingbetween the screw threads of the cap and lugs of the neck bottle whichin effect form a continuous channel for the liberated gas to escape.

It has been found that the size of the micropores in the plastic layercan range from 1 to 50 microns with 1 to 15 microns being the preferredrange. In general a lower range of 1-5 microns and less will bepreferredwith those highly penetrative liquids of a non-viscous nature. On theother hand a pore size of 10-15 microns and higher will provesatisfactory with most gas liberating liquids, viscous liquids, andsolids. Microporous plastics suitable for this purpose have recentlybecome available (see US. 2,794,753) and include polyvinyl chloride,polyvinylidene chloride, nylon, polyethylene, polypropylene, styrene,acrylonitrile, methylmethacrylate, cellulose acetate plus derivativesand polymeric mixtures thereof.

The thickness of the microporous plastic layer can reach a maximum ofabout .1 inch in the case of the FIG. 1 modification and from about25-30/ 1000 inch to less than inch in the case of the FIG. 2 and FIG. 3modifications. Although in FIG. 2 the plastic liner is shown as beingthicker than the paperboard backing, usually the converse will be trueas shown by the following examples which illustrate the effectiveness ofthe cap construction of the present invention in preventing pressurebuild up in containers having gas liberating materials and yetmaintaining a leak proof condition with respect to the materials.

Example I Pint bottles of bleach solution (hypochlorite) were sealedwith conventional caps and caps of the type shown by FIG. 3. Afterconditioning upright at F., the bottles were turned on their sides andleakage observed after 24 hours. Any detectable amount of leakage wasconsidered unsatisfactory. The results are tabulated below usingmicroporous polyethylene having openings from 8-12 microns.

Liner Venting of gas head- Leakage of liquid Nnmspace pressures bertested Backing Facing Range, Average, Number kt 70 F.,

p.s.i.g. p.s.i.g. tested 1 day .035 in. paperboard.. .012 polyethylene12 0-2 1. 8 6 0 .040 in. paperboarcl Al foil coated with vinyl plastic"-12 47100+ 89.0 6 0 The venting test consisted of filling 30 cc. bottleswith the bleach solution to a 4 cc. headspace. Two 6-penny iron nailswere added to accelerate pressure build up, caps were applied at 18inch-lbs. torque, and bottles stored at 70 F. for 18 hours. At the endof this period, the headspace pressure was measured with a punctureneedle attached to a calibrated puncture gage.

Example II In a venting test similar to Example I involving acommercially available solid effervescent salt consisting substantiallyof sodium bicarbonate and tartaric acid the results were as follows:

In the above table, the pressures were read after 3 days storage at 125F. No leakage was observed which was expected due to the solid state ofthe salt.

The manner in which the microporous plastic particularly prevented thebuild up of excessive and dangerous pressures within the containers willbe evident from the foregoing tables. In addition no leakage occurredalthough this was not unexpected in the case of Table II.

In the case of solids which tend to liberate gases upon standing, thenovel venting closure of the present invention also appears to have thesalutary effect of inhibiting the inflow of moisture from the air sinceno caking or moisture absorption is observed to take place with theeffervescent salt of Example II. This can be explained and attributed tothe tendency of the liberated gas as it escapes to force back theentrance of the surrounding atmospheric gas. However, ultimately anequilibrium between outflow of liberated gases and inflow of surroundingatmosphere is probably reached.

It will be apparent that various modifications can be made in thepresent invention without departing from the spirit thereof. Forexample, threaded caps have been shown in the drawings and examples butthe invention is equally applicable to the well known crown or bottlecap in which the depending skirt of the cap is simply crimped againstthe side of the container or bottle neck (see US. 2,327,454 by way ofexample). Moreover, the reference to the use of the caps of the presentinvention for bleaching solutions is merely illustrative since othersolutions which tend to give off gases and which can be bottled with thevented closures of this invention include hydrogen peroxide andmolasses.

The adhesive layer 12 shown in FIGURE 3 is preferably porous in nature.However, for certain applications a non-porous adhesive can be employedwhereby edge transmission through the porous facing member is utilizedto allow the gas to escape. In addition a nonporous adhesive can beapplied in strips so that a discontinuous layer of adhesive holds theporous plastic layer to the paper board or other similar backing.

It is further understood that the vented closure of the presentinvention can be used as a cap for bottles used to contain powders whichliberate gaseous products during storage such as effervescent salts andbleaching powder (CaOCl Although with powders there is no problem ofleakage, it is still highly desirable to prevent the build up ofdangerous pressure in glass containers which can result in the actualexplosion of the containers.

From the foregoing description it will be apparent that applicants haveprovided a controlled venting of a container without leakage of theliquid (or solid) therein by employing a closure liner which ismicro-porous. This in turn depends upon the well known phenomenon thatwhether or not a liquid will pass through a given micro opening willdepend upon the size of the opening, the interfacial tension between theliquid and the solid in which the micro opening occurs and the pressuredifference tending to force the liquid through the micro opening. Byemploying the micro-porous plastic described above applicants havesucceeded in allowing the gaseous decomposition by-product to passthrough but in checking the passage of the liquid, for example,bleaching solution (hypochlorite) without the development of anysubstantial pressure within the container.

While the illustrative embodiments of the invention have been describedhereinbefore with particularity, it will-be understood that variousother modifications will be apparent to and can readily be made by thoseskilled in the art without departing from the scope and spirit of theinvention. Accordingly, it is not intended that the scope of the claimsappended hereto be limited to the examples and description set forthherein but rather that the claims be construed as encompassing all thefeatures of patenta-ble novelty which reside in the present inventionincluding all features which would be treated as equivalents thereof bythose skilled in the art to which the invention pertains.

We claim:

1. In combination a container filled with a liquid maerial containing avolatile component, said container having a neck portion with a rim anddispensing opening, and a closure cap engaging the neck of saidcontainer in a pervious relationship and having an impervious coverportion overlying the opening rim, a flat liner disc interposed betweensaid cover portion and said rim, said rim contacting the liner about theperipheral edge thereof and clamped thereagainst by said closure cap,said liner consisting of a microporous plastic material, the pores ofwhich are of such size as to prevent the escape of the materialtherethrough while accommodating the passage of the volatile componentliberated by said material.

2. The combination of claim 1 wherein the pores are 1-50 microns insize.

3. The combination of claim 1 wherein the pores are 1-5 microns and lessin size.

4. The combination of claim 1 wherein the pores are l015 microns insize.

5. The combination of claim 1 wherein the pores are 1-15 microns insize.

6. The combination of claim 1 wherein the closure is of the crown captype.

7. The combination of claim 1 wherein the closure is of the threadedtype.

8. The combination of claim 1 wherein the cover portion is metallic.

9. The combination of claim 1 wherein a further porous liner isinterposed between said cover portion of said cap and said microporousplastic liner.

10. In combination a container filled with a liquid material containinga volatile component, said container having a neck portion with a rimand a dispensing opening, and a closure cap engaging the neck of saidcontainer in a pervious relationship, said closure cap having animpervous cover portion overlying the opening rim, an interposed linerin contact with said cover portion and said rim, said rim contacting theliner about the peripheral edge thereof and clamped thereagainst by saidclosure cap, said liner consisting of a flat disc of a microporousplastic material, the pores of which are of such size that theinterfacial tension between the plastic material and the liquid materialis sufiiciently high to prevent the escape of the 5 liquid materialWhile accommodating the passage of the 2,387,730 volatile componentliberated by said liquid material. 2,626,073 2,732,092 References Dated1n the file of tlus patent UNITED STATES PATENTS 5 2,256,483 JohnstonSept. 23, 1941 457,847 2,298,938 Grlfiin et al Oct. 13, 1942 R 14,806

6 Alderson Oct. 30, 1945 Miller Ian. 20, 1953 Lawrence Jan. 24, 1956FOREIGN PATENTS Canada July 5, 1949 Germany Mar. 15, 1956

10. IN COMBINATION A CONTAINER FILLED WITH A LIQUID MATERIAL CONTAININGA VOLATILE COMPONENT, SAID CONTAINER HAVING A NECK PORTION WITH A RIMAND A DISPENSING OPENING, AND A CLOSURE CAP ENGAGING THE NECK OF SAIDCONTAINER IN A PREVIOUS RELATIONSHIP, SAID CLOSURE CAP HAVING ANIMPERVOUS COVER PORTION OVERLYING THE OPENING RIM, AN INTERPOSED LINERIN CONTACT WITH SAID COVER PORTION AND SAID RIM, SAID RIM CONTACTING THELINER ABOUT THE PERIPHERAL EDGE THEREOF AND CLAMPED THEREAGAINST BY SAIDCLOSURE CAP, SAID LINER CONSISTING OF FLAT DISC OF A MICROPOROUS PLASTICMATERIAL, THE PORES OF WHICH ARE OF SUCH SIZE THAT THE INTERFACIALTENSION BETWEEN THE PLASTIC MATERIAL AND THE LIQUID MATERIAL ISSUFFICIENTLY HIGH TO PREVENT THE ESCAPE OF THE MEANS, WHEREBY SAID LOWPRESSURE STEAM PROVIDES AT LEAST LIQUID MATERIAL WHILE ACCOMMODATING THEPASSAGE OF THE VOLATILE COMPONENT LIBERATED BY SAID LIQUID MATERIAL.